GNUPlot Manual

158 gnuplot 4.0 42 UPDATE
Additionally, for points in a grid format, splot can interpolate points having a common amplitude (see
set contour (p. 61)) and can then connect those new points to display contour lines, either directly
with straight-line segments or smoothed lines (see set cntrparam (p. 58)). Functions are already
evaluated in a grid format, determined by set isosamples and set samples, while file data must either
be in a grid format, as described in data-file, or be used to generate a grid (see set dgrid3d (p. 63)).
Contour lines may be displayed either on the surface or projected onto the base. The base projections
of the contour lines may be written to a file, and then read with plot, to take advantage of plot’s
additional formatting capabilities.
39 System
system spawns shell to execute a command. Please type help shell for more details.
40 Test
This command graphically tests or presents terminal and palette capabilities.
Syntax:
test {terminal | palette [rgb|rbg|grb|gbr|brg|bgr]}
test or test terminal creates a display of line and point styles and other useful things appropriate for
and supported by the terminal you are just using.
test palette draws graphically profiles R(z),G(z),B(z), where 0